The present invention relates to an optical switch system and apparatus for use in controlling the operations of retracting or extending a stairway (gangway) from an aircraft or opening or closing power windows of a motor vehicle.
Recently, large aircraft have been designed so that passengers can have direct access thereto from a jetway. On the other hand, smaller aircraft mainly intended to fly in and out of small local airports are generally equipped with a retractable stairway in the cabin thereof that can be extended to provide access for passengers. The mechanism for extending the stairway down to the ground or retracting it, to be accommodated in the cabin, is operated by hydraulic pressure, for example, with many pipes harnessed to the frame of the aircraft. However, such hydraulic pipes are cumbersome to handle. Instead, therefore, an electric signal has been conventionally used for controlling the operation of the stairway. In order to achieve the control by the electric signal, the necessary number of cables must be laid and provided with associated control switches. A similar approach is taken for operating power windows of a vehicle. However, because of the great number of wires that have to be harnessed, the method described above suffers from problems as to the difficulty involved in installation work and obtrusiveness of the wire harness. Further, such a conventional method with the cluttered wires may cause another problem that an erroneous operation is liable to occur particularly in an environment that is subject to heavy electromagnetic interference.
To avoid the above problems, an optical fiber cable may be used. However, in this case, it is necessary to install a light source at the operating site and, as a result, accompanying wire harnesses are still required for supplying power to the light source. Thus, the problem of limiting in the number of wires has not conventionally been sufficiently solved by employing an optical fiber cable.